LONDON, United Kingdom — Building a fashion brand is tough. An almost infinitesimal number succeed from the thousands founded each year. For every Alexander Wang, who launched his label straight out of school and has gone on to build a commercially successful brand, there are many more labels that never got off the ground to begin with.

Addressing an audience of students at Central Saint Martins in 2015, Anna Wintour advised: “The only thing I worry a little bit about, going straight from school to starting your own business, is not that many succeed… I personally would advise you to think carefully before you start your own business, and consider possibly working for a designer or a company whose work you admire.”

Gary Wassner, the founder of Hilldun, a factoring firm that provides young designers with loans and other forms of credit, and Interluxe, an investment firm, which have financed labels including Marc Jacobs, Tommy Hilfiger and Jason Wu respectively, advises aspiring designers to soak up whatever experience they can in his classes at Fordham University. “I don’t think designers right out of school understand very well how to merchandise; what gross margin is; how to manage relationships with retailers,” says Wassner. “[The market] is so complicated today that unless you have a support structure around you in a new venture, you’re going to make major mistakes… I think you learn that with experience at other brands.”

Wassner believes aspiring fashion professionals should seek out opportunities at emerging businesses because of the opportunity for wider and more varied responsibility. “Intern while you’re in school. Get as much experience as you possibly can, in a small company where you can really get a feel for what it takes to get a company going,” he says. “At brands that are under $20 million, there’s a lot of shared responsibility within the team, because you’re talking anywhere from 15 to 50 employees. You learn much, much more.”

The ability to learn more, and learn faster, makes time spent in smaller business often much more efficient and effective learning experience — at any level of seniority. “It is nearly impossible to just learn things by doing them, without having been exposed to the best practices,” adds high-powered headhunter Floriane de Saint Pierre, who placed Christopher Bailey at Burberry and Alber Elbaz at Guy Laroche. “You need to get prepared as much as you can.”

Below, BoF selects 10 of the best opportunities at some of fashion’s most exciting start-up design businesses.